Muffler with longitudinal chamber

ABSTRACT

A straight through muffler for removing medium and high frequency sounds in the exhaust system of an internal combustion engine includes a straight through gas passage that is formed by a length of wire cloth or the equivalent which is pleated so that the inner diameter of the pleats define the gas passage and the outer diameter fits the housing of the muffler.

United States Patent [191 Malkiewicz 11] 3,709,321 1 Jan. 9, 1973 [54] MUFFLER WITH LONGITUDINAL CHAMBER [75] Inventor: Wladyslaw F. Malkiewicz, Casa Grande, Ariz.

[.73] Assignee: Tenneco lnc., Racine, Wis.

[22] Filed: Aug. 19, 1971 [21] Appl. No.: 172,978

[52] US. Cl. ..l81/50, 181/56, 181/70,

181/71 [51], Int. Cl. ..F01n l/l0,F0ln 7/16 [58] Field of Search.....-.....18l/56, 49, 50, 68, 70, 71, 181/36 C, 41, 42, 46, 35 A, 35 C [56] References Cited UNITED STATES PATENTS 9/1932 Oldberg ..181/68 1,897,649 2/1933 Good ..1 8l/71 1,953,543 4/1934 Rensink... .....18l/71 2,185,584 1/1940 Boyce ..l8l/7l 3,100,140 8/1963 Ashley et a1. .181/36 C 3,134,457 5/1964 Marcellus ..181/7l 3,243,010 3/1966 Flynn ..181/50 Primary Examiner-Robert S. Ward, Jr. Attorney-J. King Harness et al.

[57] ABSTRACT A straight through muffler for removing medium and high frequency sounds in the exhaust system of an internal combustion engine includes a straight through gas passage that is formed by a length of wire cloth or the equivalent which is pleated so that the inner diameter of the pleats define the gas passage and the outer diameter fits the housing of the muffler.

5 Claims, 2 Drawing Figures MUFFLER WITH-I LONGITUDINAL CHAMBER BRIEF SUMMARY OF THE INVENTION his the purpose of this invention to provide an improved muffler of the straight through flow type that is commonly used on automobileswhere it is desired to retain some of the low frequency power indicating sound in the exhaust system.

The invention accomplishes this by means of a structure in which the usual straight through gas passage is formed by a fibrous sheet, such as wire cloth. This is preferably pleated with the pleats extending radially with respect to the direction of flow to the muffler.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross section through a muffler embodying the invention; and.

FIG. 2 is an enlarged partial section along the line 2-2 of FIG. 1.

DESCRIPTION OF THE INVENTION The muffler 101 has a housing or outer shell 103 which is preferably circular and tubular in shape and reduced in diameter at its inlet and outlet ends to form inlet and outlet bushings 105 and 107 that may be slotted at 109 to facilitate clamping to the exhaust pipe and tailpipe of an exhaust system for an internal combustion engine. Near the inlet end of the shell 103 is positioned an inner partition 111 that has an outer circumferential flange 113 that is fixed to the shell as by spotwelding; near the outlet end of the shell is a partition 115 that has a circumferential flange that is affixed to the shell as by means of spotwelds indicated by the small xs in the drawings. The partitions 1.11 and 115 have necks 119 and 121 respectively formed in them and which extend toward each other and are coaxial with each other and preferably with the shell 103 as well as with the inlet and outlet bushings 105 and 107. The space between the partition 111 and the bushing 105 comprises an inlet chamber 123 while the space between the partition 115 and the busing 107 comprises an outlet chamber 125. The chambers 123 and 125 are larger in diameter than either of the two openings for gas which communicate with them and therefore function to some degree as expansion chambers to remove sound energy to attenuate sound in exhaust gas flowing through the muffler.

The chamber 127 between the partition 111 and the partition 115 in conventional mufflers of this type normally contains a cylinder or tube of packed fibrous material, such as asbestos or fiber glass or the like, which is very effective in removing high and medium frequencies as the gas flows through the muffler, such a design permitting powerful sounding low frequencies, favoredby sports car enthusiasts to remain within the audible range.

In the present muffler the conventional packing is omitted and instead a tubular, pervious, fibrous sheet 129 with its axis substantially coaxial with that of the inlet and outlet is used. The sheet 129 has longitudinally extending V-shaped folds therein, i.e., it is pleated in a radial direction, each side 131 of the pleat extending longitudinally the full distance between the partition 111 and the partition 115. The member 129 may be pleated while his in sheet form and then rolled into a tube and the longitudinal edges connected together in a suitable manner. While wire cloth is the preferred material, woven glass fiber sheets or other equivalent materials may be used. The inner turns 133 of the pleated sides define the inner diameter of a gas passage flowing through the chamber 127 and are sized to seat on the outer diameter of the necks 1 19 and 121. The outer turns 135 fit the inside of the wall of the shell 103.

It will be seen that the sides 131 define longitudinally extending chambers 137 and 139 which extend circumferentially around the axis of the muffler. These chambers are closed at opposite ends by the imperforate walls of the partitions 111 and 115. The inner diameter of the chamber 139 opens directly into the gas passage 141 that is defined by the inner turns 133 of the member 129 whereas the chambers 137 communicate with the gas passage 141 as well as adjacent chambers 139 through the thickness of the fibrous walls 131. Thus, pulses of gas flowing into the chamber 127 and along the passage 141 can expand radially into chambers 139 without resistance and with some attenuation due to the expansion. Further expansion into the chambers 137 meets with the resistance and sound absorbing characteristics of the fibrous material which is particularly effective in removing high frequency sound and roughness.

In operation, gas enters the inlet bushing and flows into the inlet chamber 123 and from there goes along the passage 141 until it reaches the outlet chamber from which it flows through outlet bushing 107. Sound attenuation enroute is achieved by the expansion chambers 123 and 125 and by general loss of energy as the gas expands into and passes through the pleated perforate sheet 129.

Modifications may be made without departing from the spirit and scope of the invention.

lclaim:

1. A sound attenuating muffler comprising an elongated shell having an inlet and an outlet and a longitudinally extending chamber located between and connecting said inlet and outlet, and a tubular fibrous sheet member located in and extending longitudinally of said chamber, said member having longitudinally extending radially formed substantially V-shaped folds therein.

2. In a sound attenuating muffler, means forming a straight gas passage for gas comprising a tubularly shaped pervious fibrous member having a longitudinal axis defining said straight through passage, said member having angularly spaced radially directed and longitudinally extending pleats formed therein.

3. A sound attenuating muffler comprising an elongated shell having an inlet at one end and an outlet at the other end, a pair of transverse partitions in said shell, the space in said shell between said partitions comprising a longitudinally extending chamber, and a gas pervious tubular member in said chamber and defining a gas passage through the chamber, said member having a pleated wall with the outer diameter of the pleats adjacent the inside of the shell and the inner diameter of the pleats defining a straight through gas passage through said chamber. 1

4. A muffler as set forth in claim 3 whe'rein said partitions have necks formed thereon and the inner diameter of ends of the pleats is supported by said necks.

5. A muffler as set forth in claim 3 including end expansion chambers between said partitions and the ends of the shell and located in the path of gas flowing from the inlet to the outlet.

4: w k w w 5 

1. A sound attenuating muffler comprising an elongated shell having an inlet and an outlet and a longitudinally extending chamber located between and connecting said inlet and outlet, and a tubular fibrous sheet member located in and extending longitudinally of said chamber, said member having longitudinally extending radially formed substantially V-shaped folds therein.
 2. In a sound attenuating muffler, means forming a straight gas passage for gas comprising a tubularly shaped pervious fibrous member having a longitudinal axis defining said straight through passage, said member having angularly spaced radially directed and longitudinally extending pleats formed therein.
 3. A sound attenuating muffler comprising an elongated shell having an inlet at one end and an outlet at the other end, a pair of transverse partitions in said shell, the space in said shell between said partitions comprising a longitudinally extending chamber, and a gas pervious tubular member in said chamber and defining a gas passage through the chamber, said member having a pleated wall with the outer diameter of the pleats adjacent the inside of the shell and the inner diameter of the pleats defining a straight through gas passage through said chamber.
 4. A muffler as set forth in claim 3 wherein said partitions have necks formed thereon and the inner diameter of ends of the pleats is supported by said necks.
 5. A muffler as set forth in claim 3 including end expansion chambers between said partitions and the ends of the shell and located in the path of gas flowing from the inlet to the outlet. 